88 Stratos LV/LV-T Technical Manual
2.8Mode Switching
Mode switching prevents the conduction of paroxysmal atrial tachycardias to the ventricle. Therefore, after sensing an atrial tachycardia while in activated mode switching, the CRT-P automatically switches to an atrial-controlled R- mode. Like the programmed atrial-controlled P-mode, the corresponding R-modes can be programmed:
Table 21. Mode Switching
Programmed P mode | Programmed R mode in case of |
| sensed atrial tachycardias |
DDD | DDI |
DDD | DDIR |
DDDR | DDIR |
VDD | VDI |
VDD | VDIR |
VDDR | VDIR |
DDTA | DDI |
DDTA | DDIR |
DDTAR | DDIR |
The Mode Switching algorithm causes the CRT-P to change pacing modes when a programmed number of atrial intervals
(X)out of 8 consecutive atrial intervals (p-p) are faster than the programmed mode switch intervention rate (X out of 8). X is programmable from 3 to 8. The rate at which an atrial interval is determined to signify an atrial tachyarrhythmia is called the mode switch intervention rate. The mode switch intervention rate is programmable from 100…(10)…250 bpm.